Abstract
In order to study histogenesis of the vaginal anlage in the feminized male fetuses, male fetuses which were obtained from pregnant mice treated with 6 mg of cyproterene acetate (CA) from day 14 of pregnancy were sacrificed at different fetal ages and examined histologically. The formation of vaginal anlage was evident at day 18 of pregnancy in female and CA-treated male fetuses. In the feminized male fetuses, the most part of the Müllerian duct degenerated and only the fused part of Müllerian duct which was close to the urogenital sinus remained. At the same time, the formation of the vaginal plate from the dorsal wall of the urogenital sinus occurred. Thus, the origin of vaginal anlage of CA-induced feminized males seemed to be similar to that of the female; the cranial part originated from the fused Müllerian duct and the caudal part arising from the urogenital sinus.
In order to study the dose-effects of CA on the development of the male reproductive tracts and the vaginal anlage in male offsprings, 1, 3, or 6 mg of CA was injected to pregnant mothers from days 14 to 20 of pregnancy. In CA-treated (feminized) males, the development of bulbourethral gland, coagulating gland and prostate were inhibited under the CA influence. The degree of inhibition of these organs by CA treatment was highly correlated with the dosage of CA. The vaginal plate formed from the urogenital sinus in male receiving 6 mg of CA showed the almost same shape as the vaginal plate of newborn females. However, with 3 mg of CA, the formation of the vaginal plate was markedly modified. In males exposed to 1 mg of CA, further modification was observed and the formation of vaginal plate was incomplete.
These results suggest the possible inhibitory and stimulatory roles of androgen in the differentiation of vagina and male reproductive tract.
